This is PDF file for basic knowledge of Importance of transformer in power system

1. NAME : Md. Selim Islam
ID: 201-33-5321
SECTION: A
DEPARTMENT: EEE (Eve)
CROUSE NAME: Energy Conversion I
CROUSE CODE: EEE-213
TOPIC: Importance of transformers in power system
WELCOME TO MY PRESENTION

2. What is a Transformer ?
A transformer is defined as a passive electrical device that transfers electrical energy from one
circuit to another through the process of electromagnetic induction. It is most commonly used
to increase (‘step up’) or decrease (‘step down’) voltage levels between circuits.

4. What is Power Transformer?
One of the important and commonly used Transformer is Power transformer. It is very widely used for
stepping up and stepping down the voltage at the electrical power generating station and
distribution station (or substation) respectively. For example, consider the block diagram shown
above. Here power transformer is used two times while delivering electric power to a consumer who is
far away from the generating station. First time is at power generating station to step-up the voltage
generated by the wind generator. Second is at the distribution station (or substation) to step-down the
voltage received at the end of the transmission line.

5. Why transformers are used in power system?
 industrial developed countries have electrical transmission and distribution system which is used to
transfer electrical energy from generating station to user end. The devices which used electrical
power is called load. Usually loads are designed according to power and voltage rating. But usually
voltage rating of load devices is not more than a 750 volt. In many countries , generating stations are
usually long distance away from loads. That is why we need to transmission of electrical energy from
remotely located generating stations to load. But the main issue in transmission of electrical energy
from log distance is efficiency of power system. Because line losses of lines increase with the increase
in length of lines. So we need a method to reduce line losses using some instrument. It is also
necessary to maintain terminal voltages at the terminals of the load. In power system users turn on or
turn off power according to their requirement. Therefore total load is also variable. Due to line losses
require terminal voltage at the load end reduces which is not suitable for load. It also damage loads.
According to standard distribution system, voltage variation to load should not be greater than ±10 of
rating of load. Otherwise load do not work properly. It may also damage load permanently. Therefore
we also need to maintain voltage at load terminal. Voltage drops on lines should not be greater than
a specified limit. In case of dc current transmission and distribution we have to face such issues. To
solve these issues transformers are used in power system. To avoid line losses and voltage drop in lines,
transmission of electrical power carried out at maximum voltage. To step up voltage transformers are
used in power system. Line losses ( voltage drops) can be reduced by transmission of electrical power
at higher voltages. Because power transmitted over transmission lines is equal to product of voltage
and current. Because power remain constant. By increasing voltage to maximum, current decrease
to low value to maintain power constant. In this way line losses are also reduced.

6.  In this way by transmission of electrical power at higher voltages using transformers less current is
required. It is difficult to step up dc voltages than transformers. But dc voltage can be step up to certain
which is not enough to get maximum efficiency of power system. Power transformers are most suitable
option for this purpose. That is why AC power system is more preferable than DC power system. There
are many types of transformer and many purpose of transformers. But the basic purpose of transformers
are to step up voltage at generation end and step down voltage at user end. Transformers works on the
principle induction. Other than this transformers are used to for many applications. Some of the
applications of transformers are given below:
 they are used for AC motor starting.
 Isolated .
 Phase shifter .
 impedance matching.
 current
 Potential
 Auto